Traditional array-based RADAR receivers calculate azimuth and/or elevation by measuring the time or phase difference between received probe signals at different receivers (or antennas) within the array(s) using beamforming (e.g., digital beamforming). Similar effects may be produced using a transmit array instead of a receiver array. These traditional solutions are limited: angular resolution depends both on the number of elements in the array and the angle between the array and the target:
      θ    resolution    ≈      λ          Nd      ⁢                          ⁢      cos      ⁢                          ⁢      θ      where N is the number of elements in the array and d is the distance separating them.
Thus, there is a need in the radar field to create new and useful systems and methods for 4-dimensional radar tracking. This invention provides such new and useful systems and methods.